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纸基摩擦材料纤维、树脂含量和孔隙率对压缩回弹性能的影响 总被引:2,自引:0,他引:2
纸基摩擦材料属多孔材料,其摩擦磨损性能与压缩回弹性能密切相关。研究了纸基摩擦材料纤维的含量及类型、树脂的含量,以及材料的孔隙率对其压缩回弹性能的影响。结果表明,材料配方及孔隙率会显著改变材料的压缩率和回弹率。纤维和树脂含量的增加都会造成纸基摩擦材料压缩率的降低和回弹率的升高。其中,树脂含量对材料压缩率的影响较大,纤维含量对材料回弹率的影响较大。加入混杂纤维的材料比较单纯采用芳纶纤维浆粕的材料具有更低的压缩率和更高的回弹率,其中混杂有纸浆纤维的材料压缩回弹性能最好。纸基材料的孔隙率越大,材料压缩率越大,回弹率越低。 相似文献
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本文比较了三种不同方法测得的柔性石墨压缩率和回弹率结果,并研究了密度、膨化倍率、粒度和纯度对压缩回弹性能的影响. 相似文献
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研究了国内三种不同生产工艺的柔性石墨板材的压缩回复性,结果表明随压缩应力的增加和板材密度的减小,板材压缩率增大,而回弹率降低.在相同的压缩应力下板材的压缩回弹性也受其密度的影响,即随密度的增加,板材的压缩率降低,回弹率提高。 相似文献
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目的结合人眼视觉特性,研究一种基于改进量化表的JPEG图像压缩算法(JPEG-HVS)。方法利用人眼亮度对比度敏感函数(CSF)生成一种新的量化表,来代替传统JPEG标准推荐的亮度量化表,并通过Matlab7.0对不同种类图像进行了仿真实验。通过计算不同种类图像的压缩质量评价指标,将提出的压缩算法与传统JPEG压缩算法及JPEG区域法进行对比。结果 JPEG-HVS实现的压缩比比JPEG实现的压缩比平均高出53.56%,比JPEG区域法平均高出18.75%。3种压缩方法的峰值信噪比(PSNR)波动不大,JPEG的PSNR值最大,JPEG-HVS次之,平均结构相似度(MSSIM)从大到小排列依次为JPEGJPEG-HVSJPEG区域法。JPEG-HVS编解码所需时间要明显少于JPEG。同时依靠主观评价可以发现,经JPEG-HVS解压的重构图像仍具有良好的视觉特性。结论在保证了压缩质量的同时,提出的JPEG-HVS压缩算法相比于传统JPEG压缩算法、JPEG区域法,可以实现更大的压缩比和更快的编解码速度,更有利于图像的存储与传输。 相似文献
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电子摄像机和放映机的质量提高得很快。数据加工器件计算能力的提高使图像数据流的深度加工成为可能。压缩算法的改进使高压缩率条件下仍能保持很高的图像质量。高解像率和高帧频的结合使电子成像系统获得前所未有的图像清晰度。在高质量图像压缩的基础上,图像摄取和演示的潜力得到充分的发挥。现在,不经压缩的标清数字视频器件已广泛应用于视频系统的各个环节,大大提高视频质量又成为刻不容缓的任务,与视频质量的提高相比,上个世纪最后十年HDTV取得的进展却不尽如人意。 相似文献
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Abstract: A new test method to determine the compressive properties of composite materials under both static and fatigue loading was developed. The novel fixture is based on the concept of transmitting the load by a fixed ratio of end‐to‐shear loading. The end‐to‐shear load ratio is kept fixed during the test through a mechanical mechanism, which automatically maintains the gripping pressure. The combined loading method has proven very efficient in static loading and is used in the new fixture which is specially designed for fatigue testing. Optimum gripping (shear loading) and alignment of the test coupon are achieved throughout the fatigue life. The fatigue strength obtained is more reliable because bending of the specimen due to poor gripping and alignment is minimised. The application of the new fixture to static and fatigue compression is demonstrated by using unidirectional carbon/epoxy and glass/polyester composite systems. Repeatable results and acceptable failure modes are obtained under both static and fatigue loading. 相似文献
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Vera Penkavova L. Kulaviak M. C. Ruzicka M. Puncochar P. Zamostny 《Particulate Science and Technology》2018,36(4):432-437
In this experimental study, behavior of dry granular layers of monodisperse cylindrical particles (8?×?1?mm) under uniaxial compression in piston die arrangement was investigated. The layer compressibility and particle size distribution (PSD) were measured. It was found that neither the piston speed nor the layer size were relevant, within the experimental range. The compressibility and PSD were affected mainly by the applied load. At the single compression, with the increasing pressure, PSD moves toward smaller sizes of broken particles always leaving some initial particles intact. At the repetitive compression, the pressure had more destructive effect, resulting in larger particle fragmentation. 相似文献
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In this study, failure modes occurring during Filled hole compression (FHC) tests were analysed using post-mortem analysis for failure pattern identification and high-speed cameras for failure scenario (damage initiation and progress). Two different failure scenario were experienced depending upon the stacking sequence:
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- Net compression failure for high 0° oriented lay-ups. The crack initiation is observed near the bolt but the location differs with bolt tightening or not, enabling future validation of finite element models. 相似文献
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通过对一起双级压缩制冷系统运行故障的处理,分析制冷系统中变工况特点对制冷系统的影响,提出根据变工况特性合理选择高低压容积比的重要性。 相似文献
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该文介绍了油封机械泵的抽速与入口压力的关系、泵抽气效率下降的原因,指出泵入口管道的流导和油蒸汽逆流是造成泵抽速下降的主要原因.其次,还对油封机械泵的消耗功率与入口压力的关系进行了分析,指出最大功率时所对应的入口压力,同时还对泵油温度对功率的影响作了分析;给出对泵油性能的要求. 相似文献
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通过构造特别的映射、整函数和BP神经网络,获得一套基于神经网络的无损数据压缩方案。由于该方案能压缩已被小波编码压缩过的数据,因此将其嵌套入一好的小波编码系统就可以获得一种基于小波与神经网络的高效图像数据压缩方案。实验证明,该高效方案对于Lenna图像的压缩比为43∶1, 并且恢复的图像有较好的视觉效果。 相似文献